Light emitting device and light unit

ABSTRACT

Provided are a light emitting device, a method of fabricating the light emitting device, and a light unit. The light emitting device includes a light emitting structure layer comprising a first conductive type semiconductor layer, an active layer under the first conductive type semiconductor layer, and a second conductive type semiconductor layer under the active layer, a first conductive layer under the second conductive type semiconductor layer and electrically connected to the first conductive type semiconductor layer, a second conductive layer under the second conductive type semiconductor layer and electrically connected to the second conductive type semiconductor layer, an insulation layer between the first conductive layer and the second conductive layer, and a tunnel barrier under the second conductive type semiconductor layer and disposed between the first conductive layer and the second conductive layer.

The present application claims priority under 35 U.S.C. 119 to KoreanPatent Application No. 10-2010-0063636 filed Jul. 1, 2010, which ishereby incorporated by reference in its entirety.

BACKGROUND

Embodiments relates to a light emitting device, a method of fabricatingthe light emitting device, and a light unit.

Group III-V nitride semiconductors are spotlighted as core materials oflight emitting diodes (LEDs) or laser diodes (LDs) due to their physicaland chemical characteristics.

Such a light emitting device converts electrical signals into light suchas infrared rays or visible rays using characteristics of compoundsemiconductors. In recent, as light efficiency of the light emittingdevice is increased, the light emitting device is being used in variousfields such as display devices and lighting devices.

SUMMARY

Embodiments provide a light emitting device having a new structure, amethod of fabricating the light emitting device, and a light unit.

Embodiments also provide a light emitting device in which a lightemitting structure layer is protected from an electrostatic discharge(ESD), a method of fabricating the light emitting device, and a lightunit.

In one embodiment, a light emitting device comprises: a light emittingstructure layer comprising a first conductive type semiconductor layer,an active layer under the first conductive type semiconductor layer, anda second conductive type semiconductor layer under the active layer; afirst conductive layer under the second conductive type semiconductorlayer and electrically connected to the first conductive typesemiconductor layer; a second conductive layer under the secondconductive type semiconductor layer and electrically connected to thesecond conductive type semiconductor layer; an insulation layer betweenthe first conductive layer and the second conductive layer; and a tunnelbarrier under the second conductive type semiconductor layer anddisposed between the first conductive layer and the second conductivelayer.

In another embodiment, a light unit comprises: a board; a light emittingdevice on the board; and an optical member through which light providefrom the light emitting device is transmitted, wherein the lightemitting device comprises: a light emitting structure layer comprising afirst conductive type semiconductor layer, an active layer under thefirst conductive type semiconductor layer, and a second conductive typesemiconductor layer under the active layer; a first conductive layerunder the second conductive type semiconductor layer and electricallyconnected to the first conductive type semiconductor layer; a secondconductive layer under the second conductive type semiconductor layerand electrically connected to the second conductive type semiconductorlayer; an insulation layer between the first conductive layer and thesecond conductive layer; and a tunnel barrier under the secondconductive type semiconductor layer and disposed between the firstconductive layer and the second conductive layer.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features will be apparent fromthe description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a light emitting device according to anembodiment.

FIGS. 2 to 9 are views illustrating a process of fabricating the lightemitting device according to an embodiment.

FIG. 10 is a sectional view of a light emitting device according toanother embodiment.

FIG. 11 is a view illustrating a process of fabricating the lightemitting device according to another embodiment.

FIG. 12 is a sectional view of a light emitting device according toanother embodiment.

FIG. 13 is a sectional view of a light emitting device packagecomprising the light emitting device according to an embodiment.

FIG. 14 is a perspective view illustrating an example of a displaydevice according to an embodiment.

FIG. 15 is a perspective view illustrating another example of a displaydevice according to an embodiment.

FIG. 16 is a perspective view of a light device according to anembodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the descriptions of embodiments, it will be understood that when alayer (or film), a region, a pattern, or a structure is referred to asbeing ‘on’ a substrate, a layer (or film), a region, a pad, or patterns,it can be directly on another layer or substrate, or intervening layersmay also be present. Further, it will be understood that when a layer isreferred to as being ‘under’ another layer, it can be directly underanother layer, and one or more intervening layers may also be present.Further, the reference about ‘on’ and ‘under’ each layer will be made onthe basis of drawings.

In the drawings, the thickness or size of each layer is exaggerated,omitted, or schematically illustrated for convenience in description andclarity. Also, the size of each element does not entirely reflect anactual size.

Hereinafter, embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is a sectional view of a light emitting device 100 according toan embodiment.

Referring to FIG. 1, the light emitting device according to anembodiment may comprise a light emitting structure layer 125, a firstconductive layer 170, a second conductive layer 140, an insulation layer150, a tunnel barrier 160, a conductive support substrate 180, and anelectrode 141.

The light emitting structure layer 125 may comprise a first conductivetype semiconductor layer 110, an active layer 120 under the firstconductive type semiconductor layer 110, and a second conductive typesemiconductor layer 130 under the active layer 120.

Electrons and holes supplied from the first and second conductive typesemiconductor layers 110 and 130 are recombined with each other in theactive layer 120 to generate light. Here, the electrons or holes may besupplied from the first conductive type semiconductor layer 110, andalso, the holes or electrons may be supplied from the second conductivetype semiconductor layer 130.

The first conductive type semiconductor layer 110 may be formed of agroup III-V compound semiconductor in which a first conductive typedopant is doped, e.g., a semiconductor material having a compositionalformula of In_(x)Al_(y)Ga_(1-x-y)N 0≦y≦1, 0≦x+y≦1). For example, thefirst conductive type semiconductor layer 110 may be formed of one ofGaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP,and AlGaInP. When the first conductive type semiconductor layer 110 isan N-type semiconductor layer, the first conductive type dopant maycomprise an N-type dopant such as Si, Ge, Sn, Se, and Te. The firstconductive type semiconductor layer 110 may have a single or multilayered structure, but is not limited thereto.

The active layer 120 may be disposed under the first conductive typesemiconductor layer 110. Also, the active layer 120 may have one of asingle quantum well structure, a multi quantum well (MQW) structure, aquantum dot structure, and a quantum wire structure. The active layer120 may have a cycle of a well layer and a barrier layer using the groupIII-V compound semiconductor material. For example, the active layer 120may have a cycle of an InGaN well layer/GaN barrier layer or a cycle ofan InGaN well layer/AlGaN barrier layer.

When the active layer 120 has the quantum well structure, the activelayer 120 may have a single or multi quantum well structure comprising awell layer having a compositional formula of In_(x)Al_(y)Ga_(1-x-y)N(0≦x≦1, 0≦y≦1, 0≦x+y≦1) and a barrier layer having a compositionalformula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1). The welllayer may be formed of a material having an energy band gap less thanthat of the barrier layer.

The second conductive type semiconductor layer 130 may be disposed underthe active layer 120. Also, the second conductive type semiconductorlayer may be formed of a group III-V compound semiconductor in which asecond conductive type dopant is doped, e.g., a semiconductor materialhaving a compositional formula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1,0x+y≦1). For example, the second conductive type semiconductor layer 130may be formed of one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN,AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the second conductive typesemiconductor layer 130 is a P-type semiconductor layer, the secondconductive type dopant may include a P-type dopant such as Mg and Zn.

The light emitting structure layer 125 may further comprise asemiconductor layer having a polarity opposite to that of the secondconductive type semiconductor layer 130 under the second conductive typesemiconductor layer 130. Also, the first conductive type semiconductorlayer 110 may be a P-type semiconductor layer, and the second conductivetype semiconductor layer 130 may be an N-type semiconductor layer. Thus,the light emitting structure layer 125 may have at least one of an N-Pjunction structure, a P-N junction structure, an N-P-N junctionstructure, and a P-N-P junction structure.

The first conductive layer 170 may be disposed under the secondconductive type semiconductor layer 130. A portion of the firstconductive layer 170 may be disposed in a recess passing through theactive layer 120 and the second conductive type semiconductor layer 130and electrically connected to the first conductive type semiconductorlayer. The recess may be called a via. The first conductive layer 170may contact the first conductive type semiconductor layer 110.

The first conductive layer 170 may be formed of at least one of Al, Ti,Cr, Ni, Cu, Au, Sn, and Ca.

Also, the first conductive layer 170 may have a multi layered structure.For example, a first layer constituting an upper region of the firstconductive layer 170 may be formed of a material for ohmic-contactingthe first conductive type semiconductor layer 110 and thus electricallyconnected to the first conductive type semiconductor layer 110. A thirdlayer constituting a lower region of the first conductive layer 170 maybe formed of a material having a superior adhesion force to easilyadhere to an external electrode. A second layer between the first layerand the third layer may be formed of at least one of a diffusion barriermetal material such as Ni for preventing interlayer diffusion and ametal material such as Cu having superior conductivity.

The second conductive layer 140 may be disposed under the secondconductive type semiconductor layer 130. The second conductive layer 140may be electrically connected to the second conductive typesemiconductor layer 130.

The insulation layer 150 may be disposed between the first conductivelayer 170 and the second conductive layer 140. The insulation layer 150may be disposed in the recess which passes through a portion of thesecond conductive type semiconductor layer 130 and a portion of theactive layer 120. The insulation layer 150 may be disposed between thefirst conductive layer 170 and the second conductive type semiconductorlayer 130. Also, the insulation layer 150 may be disposed between thefirst conductive layer 170 and the active layer 120.

The tunnel barrier 160 may be disposed between the first conductivelayer 170 and the second conductive layer 140. The tunnel barrier 160may be disposed under the second conductive type semiconductor layer130.

The conductive support substrate 180 may be disposed under the firstconductive layer 170. The electrode 141 may be electrically connected tothe second conductive layer 140. The electrode 141 may be disposed onthe second conductive layer 140.

The light emitting structure layer 125 may comprise a recess in whichportions of the regions of the active layer 120 and the secondconductive type semiconductor layer 130 are etched to expose the firstconductive type semiconductor layer 110. Also, the recess may be formedby etching portions of the regions of the second conductive typesemiconductor layer 130, the active layer 120, the first conductive typesemiconductor layer 110. The first conductive layer 170 may contact thefirst conductive type semiconductor layer 130 through the recess. Amethod of fabricating the recess will be described below in detail.

Although a side surface of the recess in the light emitting structurelayer 125 is vertically provided in FIG. 1, the recess may have a widthgradually increasing or decreasing from the second conductive typesemiconductor layer 130 toward the first conductive type semiconductorlayer 110, i.e., a width having a trapezoid shape. For example, therecess may be formed so that a portion at which the first conductivetype semiconductor layer 110 is disposed has a width less than that of aportion at which the second conductive type semiconductor layer 130 isdisposed.

The first conductive layer 170 and the insulation layer 150 may bedisposed in the recess.

The second conductive layer 140 may be disposed under the secondconductive type semiconductor layer 130. The second conductive layer 140may be disposed between the second conductive type semiconductor layer130 and the tunnel barrier 160. That is, the second conductive layer 140may be electrically connected to the second conductive typesemiconductor layer 130. Also, the second conductive layer 140 togetherwith the first conductive layer 170 may provide a power into the lightemitting structure layer 125. For example, the second conductive layer140 may directly contact the second conductive type semiconductor layer130.

For example, the second conductive layer 140 may have a single or multilayered structure and be formed of at least one of Cu, Ag, Al, Ni, Ti,Cr, Pd, Au, and Sn, but is not limited thereto.

The first conductive layer 170 may be disposed under the most region ofa bottom surface of the light emitting structure layer 125 according toan embodiment.

In the light emitting device 100 according to an embodiment, the firstand second conductive layers 170 and 140 for supplying a power into thelight emitting structure layer 125 are disposed on the bottom or sidesurface of the light emitting structure layer 125. Thus, light extractedinto a top surface direction of the light emitting device 100 may not beabsorbed by the first and second conductive layers 170 and 140.Accordingly, light extraction efficiency according to an embodiment canbe increased.

The first and second conductive layers 170 and 140 may be disposed underthe light emitting structure layer 125 according to an embodiment. Heatgenerated in the light emitting structure layer 125 may be effectivelydissipated through the first and second conductive layers 170 and 140 tothe outside.

The first and second conductive layers 170 and 140 may support the lightemitting structure layer 125.

The first conductive layer 170 may be disposed to pass through theactive layer 120 and the second conductive type semiconductor layer 130.An upper region of the first conductive layer 170 may contact the firstconductive type semiconductor layer 110, and thus be electricallyconnected to the first conductive type semiconductor layer 110. Theinsulation layer 150 for preventing the light emitting structure layer125 from being electrically short-circuited therein may be disposed on aside surface of the first conductive layer 170.

The insulation layer 150 may be disposed between a side surface of thefirst conductive layer 170 and the light emitting structure layer 125.Also, the insulation layer 150 may be disposed between the firstconductive layer 170 and the second conductive layer 140.

The insulation layer 150 may be formed of a light-transmitting andinsulating material. The insulation layer 150 may be realized usingoxide or nitride. For example, the insulation layer 150 may be formed ofat least one of SiO₂, SiO_(x), SiO_(x)N_(y), Si₃N₄, Al₂O₃, and TiO_(x),but is not limited thereto.

The insulation layer 150 for preventing the light emitting structurelayer 125 from being electrically short-circuited therein may bedisposed on a side surface of the first conductive layer 170. Also, theinsulation layer 150 may be disposed at a portion of a region definedunder the second conductive layer 140.

The tunnel barrier 160 may be disposed in a lower region of the secondconductive layer 140 on which the insulation layer 150 is not disposed.The tunnel barrier 160 may be formed of the same material as that of theinsulation layer 150 or a material different from that of the insulationlayer 150. The tunnel barrier 160 may have a thickness less than that ofthe insulation layer 150. For example, the tunnel barrier 160 may have athickness of about 1 nm to about 20 nm.

The tunnel barrier 160 may be formed of a dielectric compound comprisingat least one of materials comprising oxide, nitride, and fluoride. Forexample, the tunnel barrier 160 may be formed of at least one of SiO₂,Si_(x)N_(y), TiO₂, MgF₂, and Al₂O₃, and have a single or multi layeredstructure.

When the tunnel barrier 160 has a thickness less than that of theinsulation layer 150, thermal dissipation efficiency may be improved.Accordingly, reliability of the device can be improved. For example, thetunnel barrier 160 may be disposed on an area of about 80% to about 90%of that of the second conductive type 140.

The tunnel barrier 160 may be disposed between the first conductivelayer 170 and the second conductive layer 140 to constitute the lightemitting structure layer 125 and a parallel circuit.

A withstanding voltage characteristic of the light emitting device 100may be improved by the tunnel barrier 160. For example, when anovercurrent is significantly applied into the first and secondconductive layers 170 and 140, the overcurrent may be bypassed throughthe tunnel barrier 160 to prevent the light emitting structure layer 125from being damaged. Accordingly, the light emitting device 100 havingthe improved withstanding voltage characteristic can be provided.

The electrode 141 may be formed of at least one material of Ti, Al, In,Ta, Pd, Co, Ni, Si, Ge, Ag, Au, Hf, Pt, Ru, and Au or alloys thereof andhave a single or multi layer structure. The electrode 141 may bedisposed on the second conductive layer 140 to supply a power into thesecond conductive type semiconductor layer 130.

The conductive support substrate 180 may support the light emittingstructure layer 125 and be electrically connected to the firstconductive layer 170 to supply a power into the first conductive typesemiconductor layer 110. The conductive support substrate 180 may beformed of titanium (Ti), chrome (Cr), nickel (Ni), aluminum (Al),platinum (Pt), gold (Au), tungsten (W), copper (Cu), molybdenum (Mo),copper-tungsten (Cu—W), and a carrier wafer (e.g., Si, Ge, GaN, GaAs,ZnO, SiC, SiGe) that is a semiconductor substrate in which impuritiesare injected.

The conductive support substrate 180 may have a thickness variedaccording to a design of the light emitting device 100. For example, theconductive support substrate 180 may have a thickness of about 50 μm toabout 300 μm. It is unnecessary to provide the conductive supportsubstrate 180. When the first conductive layer 170 has a sufficientlythick thickness, the conductive support substrate 180 may be omitted.

As described above, the light emitting device 100 according to anembodiment may comprise the tunnel barrier 160 connected to the lightemitting structure layer 125 in parallel to prevent the light emittingstructure layer 125 from being damaged by a high voltage.

Hereinafter, a method of fabricating the light emitting device accordingto an embodiment will be described in detail. However, duplicatedescriptions, which have been described already in the previousexemplary embodiments, will be omitted or described briefly.

FIGS. 2 to 9 are views illustrating a process of fabricating the lightemitting device 100 according to an embodiment.

Referring to FIG. 2, a light emitting structure layer 125 may be formedon a growth substrate 105.

The growth substrate 105 may be formed of at least one of sapphire(Al2O3), SiC, GaN, ZnO, AlN, GaAs, β-Ga2O3, GaP, InP, Ge, but is notlimited thereto.

The light emitting structure layer 105 formed on the growth substrate105 may comprise a first conductive type semiconductor layer 110, anactive layer 120, and a second conductive type semiconductor layer 130.The active layer 120 is disposed between the first conductive typesemiconductor layer 110 and the second conductive type semiconductorlayer 130.

The light emitting structure layer 125 may be formed using a method suchas metal organic chemical vapor deposition (MOCVD), chemical vapordeposition (CVD), plasma-enhanced chemical vapor deposition (PECVD),molecular beam epitaxy (MBE), and hydride vapor phase epitaxy (HVPE),but is not limited thereto.

A buffer layer and an undoped semiconductor layer may be further formedbetween the growth substrate 105 and the first conductive typesemiconductor layer 110 to reduce differences in lattice constants andthermal expansion coefficients therebetween and to improve crystallineof the light emitting structure layer 125.

The first conductive type semiconductor layer 110 may be formed of agroup III-V compound semiconductor in which a first conductive typedopant is doped, e.g., one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN,AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the first conductivetype semiconductor layer 110 is an N-type semiconductor layer, the firstconductive type dopant may include N-type dopants such as Si, Ge, Sn,Se, and Te. The first conductive type semiconductor layer 110 may beformed in a single or multi layer, but is not limited thereto.

The active layer 120 may be formed on the first semiconductor layer 110.The active layer 120 may have one of a single quantum well structure, amulti quantum well (MQW) structure, a quantum dot structure, and aquantum wire structure, but is not limited thereto. For example, whenthe active layer 120 has the MQW structure, the active layer 120 mayhave a cycle of a well layer and a barrier layer, e.g., an InGaN welllayer/GaN barrier layer or a cycle of an InGaN well layer/AlGaN barrierlayer using the group III-V compound semiconductor material. The welllayer may be formed of a material having a band gap less than that ofthe barrier layer.

A conductive type clad layer may be formed above or/and under the activelayer 120. The conductive type clad layer may be formed of anAlGaN-based semiconductor and may have a band gap greater than that ofthe active layer 120.

The second conductive type semiconductor layer 130 may be formed on theactive layer 120. The second conductive type semiconductor layer 130 maybe realized by a P-type semiconductor layer in which a P-type dopant isdoped. The second conductive type semiconductor layer 130 may be formedof a group III-V compound semiconductor in which a second conductivetype dopant is doped, e.g., one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN,AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the second conductivetype semiconductor layer 130 is the P-type semiconductor layer, thesecond conductive type dopant may comprise P-type dopants such as Mg,Zn, Ca, Sr, and Ba. The second conductive type semiconductor layer 130may have a single or multi layered structure, but is not limitedthereto.

The light emitting structure layer 125 may further comprise an N-typesemiconductor layer under the second conductive type semiconductor layer130. Also, the first conductive type semiconductor layer 110 may be aP-type semiconductor layer, and the second conductive type semiconductorlayer 130 may be an N-type semiconductor layer. Thus, the light emittingstructure layer 125 may have at least one of an N-P junction structure,a P-N junction structure, an N-P-N junction structure, and a P-N-Pjunction structure.

In the current embodiment, although the light emitting structure layer125 comprising the N-type nitride semiconductor layer containing theN-type dopant, the active layer disposed under the N-type nitridesemiconductor layer, and the P-type nitride semiconductor layercontaining the P-type dopant is mainly described, the present disclosureis not limited thereto. Also, the light emitting structure layer 125 mayhave a stacked structure and material, which are variously varied.

Referring to FIG. 3, the light emitting structure layer 125 may beselectively removed to form at least one recess 135 so that a portion ofthe first conductive type semiconductor layer 110 is exposed.

The recess 135 may be formed by an etching process comprising a wetetching process and a dry etching process or a laser process, but is notlimited thereto. The light emitting structure layer 125 in which theetching process or the laser process is performed to form the recess 135may have a side surface perpendicular or inclined with respect to abottom surface of the recess 135. The recess 135 may be perpendicular orinclined with respect to a bottom surface of the light emittingstructure layer 125.

Referring to FIG. 4, a second conductive layer 140 may be formed on thesecond conductive type semiconductor layer 130. The second conductivelayer 140 may be formed on the second conductive type semiconductorlayer 130 which is not etched in the recess formation process. Thesecond conductive layer 140 may be formed of at least one of Al, Ti, Cr,Na, Cu, and Au.

Referring to FIG. 5, an insulation layer 150 may be formed on the sidesurface of the recess 135, a portion of the bottom surface of the recess135, and a portion of the second conductive layer 140. The insulationlayer 150 may prevent the light emitting structure layer 125 from beingelectrically connected to the first conductive layer 170 that will beformed later. For example, the insulation layer 150 may be formed of atleast one of SiO₂, Si_(x)N_(y), TiO₂, MgF₂, and Al₂O₃.

The insulation layer 150 may be formed using one of deposition processessuch as E-beam deposition process, a sputtering process, and a plasmaenhanced chemical vapor deposition (PECVD) process, but is not limitedthereto.

For example, the deposition process may be performed after a mask isformed on the recess 135. Thus, the insulation layer 150 may have ashape varied according to a shape of the mask.

Referring to FIG. 6, a tunnel barrier 160 may be formed on the secondconductive layer 140 on which the insulation layer 150 is not formed.The tunnel barrier 160 may be formed of the same material as that of theinsulation layer 150 or a material different from that of the insulationlayer 150. Also, the tunnel barrier 160 may have a thickness less thanthat of the insulation layer 150. The tunnel barrier 160 may be formedof a dielectric compound comprising at least one of materials comprisingoxide, nitride, and fluoride. For example, the tunnel barrier 160 may beformed of at least one of SiO₂, TiO₂, MgF₂, and Al₂O₃, and have a singleor multi layered structure. The tunnel barrier 160 may have a thicknessless than that of the insulation layer 150. For example, the tunnelbarrier 160 may have a thickness of about 1 nm to about 20 nm. When thetunnel barrier 160 has a thickness less than that of the insulationlayer 150, thermal dissipation efficiency may be improved. Accordingly,reliability of the device can be improved.

At least one tunnel barrier 160 may be formed in the light emittingdevice 100. Here, the tunnel barrier 160 may be deposited using one ofchemical vapor deposition, physical vapor deposition, atomic layerdeposition (ALD).

When a current is applied at a predetermined voltage or less, the tunnelbarrier 160 may serve as a nonconductor. When a current is applied at avoltage greater than the predetermined voltage under an electrostaticdischarge (ESD) condition, the tunnel barrier 160 may provide a tunnelphenomenon. That is, when compared to a P-N junction structure, arelatively low resistance may occur due to the tunnel phenomenon. Thus,a current may flow into the tunnel barrier 160 under the ESD condition.A tunneling effect at which the tunnel phenomenon occurs in the tunnelbarrier 160 may be inversely proportional to a thickness of the tunnelbarrier 160.

Next, a first conductive layer 170 may be formed. The first conductivelayer 170 may contact the first conductive type semiconductor layer 110exposed by the recess 135 and cover the insulation layer 150 and thetunnel barrier 160. The first conductive layer 170 may contact a topsurface of the tunnel barrier 160 and be formed of at least one of Al,Ti, Cr, Ni, Cu, Au, Sn, and Ca.

Also, the first conductive layer 170 may have a multi layered structure.For example, a first layer constituting a lower region of the firstconductive layer 170 may be formed of a material for ohmic-contactingthe first conductive type semiconductor layer 110 and thus electricallyconnected to the first conductive type semiconductor layer 110. A thirdlayer constituting an upper region of the first conductive layer 170 maybe formed of a material having a superior adhesion force to easilyadhere to an external electrode. A second layer between the first layerand the third layer may be formed of at least one of a diffusion barriermetal material such as Ni for preventing interlayer diffusion and ametal material such as Cu having superior conductivity.

Referring to FIG. 7, a conductive support substrate 180 may be formed onthe first conductive layer 170. The conductive support substrate 180 maysupport the light emitting structure layer 125 and supply a power to thelight emitting structure layer 125. The conductive support substrate 180may be formed of titanium (Ti), chrome (Cr), nickel (Ni), aluminum (Al),platinum (Pt), gold (Au), tungsten (W), copper (Cu), molybdenum (Mo),copper-tungsten (Cu—W), and a carrier wafer (e.g., Si, Ge, GaN, GaAs,ZnO, SiC, SiGe) that is a semiconductor substrate in which impuritiesare injected.

The conductive support substrate 180 may have a thickness variedaccording to a design of the light emitting device 100. For example, theconductive support substrate 180 may have a thickness of about 50 μm toabout 300 μm.

Referring to FIGS. 7 and 8, the growth substrate 105 may be removed.

The growth substrate 105 may be removed through a laser lift off (LLO)process, chemical lift off (CLO) process or a physical polishingprocess, but is not limited thereto.

Also, to improve reliability of the fabricating process, the growthsubstrate 105 may be removed after the first conductive layer 170 isformed. However, the present disclosure is not limited to an order ofthe manufacturing process.

Also, after the growth substrate 105 is removed, remnants existing onthe exposed light emitting structure layer 125 may be removed. Then, anetching process for forming a roughness or pattern may be performed toimprove light extraction efficiency.

Referring to FIG. 9, the light emitting structure layer 125 may beetched to expose a portion of the second conductive layer 140. Anelectrode 141 may be formed on the second conductive layer 140 exposedby the etching process. The electrode 141 may be an electrode pad orhave an electrode pattern including the electrode pad. The electrodepattern may have a branched structure.

The electrode 141 may be formed of at least one material of Ti, Al, In,Ta, Pd, Co, Ni, Si, Ge, Ag, Au, Hf, Pt, Ru, and Au or alloys thereof andhave a single or multi layer structure. The electrode 141 may be formedon the second conductive layer 140 to supply a power into the secondconductive type semiconductor layer 130.

Embodiments also may provide a light emitting device in which a lightemitting structure layer 125 is protected from an electrostaticdischarge (ESD) using the tunnel barrier 160 connected to the lightemitting structure layer 125 in parallel, a method of fabricating thelight emitting device.

FIG. 10 is a sectional view of a light emitting device according toanother embodiment.

Referring to FIG. 10, a light emitting device 100B according to anotherembodiment may comprise a light emitting structure layer 125, a firstconductive layer 170, a second conductive layer 140, an insulation layer150, a tunnel barrier 160, a first electrode 172, and a second electrode142. A growth substrate 105 may be further disposed on the lightemitting structure layer 125. Alternatively, the growth substrate 105may be omitted.

The light emitting structure layer 125 may comprise a first conductivetype semiconductor layer 110, a second conductive type semiconductorlayer 130, and an active layer 120 dispose between the first conductivetype semiconductor layer 110 and the second conductive typesemiconductor layer 130.

The first conductive layer 170 may pass through the active layer 120 andthe second conductive type semiconductor layer 130 to contact the firstconductive type semiconductor layer 110. The first conductive layer 170may be electrically connected to the first conductive type semiconductorlayer 110.

The second conductive layer 140 may be disposed under the secondconductive type semiconductor layer 130. The second conductive layer 140may be electrically connected to the second conductive typesemiconductor layer 130.

The insulation layer 150 may be disposed between the first conductivelayer 170 and the second conductive layer 140. The insulation layer 150may be disposed between the first conductive layer 170 and the secondconductive type semiconductor layer 130. Also, the insulation layer 150may be disposed between the first conductive layer 170 and the activelayer 120. The insulation pattern 150 may comprise a protrusion 152.

The tunnel barrier 160 may be disposed between the first conductivelayer 170 and the second conductive layer 140. The tunnel barrier 160may be disposed under the second conductive type semiconductor layer130.

The first electrode 172 may be electrically connected to the firstconductive layer 170. The first electrode 172 may be disposed under thefirst conductive layer 170. The second electrode 142 may be electricallyconnected to the second conductive layer 140. The second electrode 142may be disposed under the second conductive layer 140. The secondelectrode 142 and the first conductive layer 170 may be insulated fromeach other by the insulation layer 150.

Each of the first electrode 172 and the second electrode 142 may beformed of at least one material of Ti, Al, In, Ta, Pd, Co, Ni, Si, Ge,Ag, Au, Hf, Pt, Ru, and Au or alloys thereof and have a single or multilayer structure. The first and second electrodes 172 and 142 may supplya power into the first and second conductive type semiconductor layers110 and 130, respectively.

FIG. 11 is a view illustrating a process of fabricating the lightemitting device according to another embodiment.

Referring to FIGS. 2 and 4, a process of forming the second conductivelayer 140 on the second conductive type semiconductor layer 130 may besimilarly applied.

Thereafter, the insulation layer 150 may be formed on a side surface ofthe light emitting structure layer 125 having the recess 135 and aportion of the second conductive layer 140. The insulation layer 150formed on a portion of the second conductive layer 140 may expose aportion of the second conductive layer 140. The insulation pattern 150may comprise a protrusion 152.

For example, the insulation layer 150 may be formed after a mask isformed on the recess 135. Thus, the insulation layer 150 may have ashape varied according to a shape of the mask.

The tunnel barrier 160 may be formed on a portion of the secondconductive layer 140 on which the insulation layer 150 is not formed.The tunnel barrier 160 may be formed of the same material as that of theinsulation layer 150 or a material different from that of the insulationlayer 150.

The first conductive layer 170 contacting the first conductive typesemiconductor layer 110 exposed by the recess 135 and covering theinsulation layer 150 and the tunnel barrier 160 may be formed. The firstconductive layer 170 may fill the recess 135 and have a height equal tothat of the protrusion 152 of the insulation layer 150.

The first electrode 172 and the second electrode 142 may be electricallyconnected to the first conductive layer 170 and the second conductivelayer 140, respectively. Each of the first electrode 172 and the secondelectrode 142 may be formed of at least one material of Ti, Al, In, Ta,Pd, Co, Ni, Si, Ge, Ag, Au, Hf, Pt, Ru, and Au or alloys thereof andhave a single or multi layer structure.

A top surface of the second electrode 142 may be flush with that of thefirst conductive layer 170. Alternatively, the first electrode 172 maybe omitted. The light emitting device may have a flip-chip structure toimprove the light extraction efficiency, realize miniaturization, andreduce thermal resistance.

FIG. 12 is a sectional view of a light emitting device according toanother embodiment.

Referring to FIG. 12, a light emitting device 100C according to anotherembodiment may comprise a light emitting structure layer 125, a firstconductive layer 170, a second conductive layer 140, an insulation layer150, a tunnel barrier 160, a first electrode 172, and a second electrode144.

The light emitting structure layer 125 may comprise a first conductivetype semiconductor layer 110, a second conductive type semiconductorlayer 130, and an active layer 120 dispose between the first conductivetype semiconductor layer 110 and the second conductive typesemiconductor layer 130.

The first conductive layer 170 may pass through the active layer 120 andthe second conductive type semiconductor layer 130 to contact the firstconductive type semiconductor layer 110. The first conductive layer 170may be electrically connected to the first conductive type semiconductorlayer 110.

The second conductive layer 140 may be disposed under the secondconductive type semiconductor layer 130. The second conductive layer 140may be electrically connected to the second conductive typesemiconductor layer 130.

The insulation layer 150 may be disposed between the first conductivelayer 170 and the second conductive layer 140. The insulation layer 150may be disposed between the first conductive layer 170 and the secondconductive type semiconductor layer 130. Also, the insulation layer 150may be disposed between the first conductive layer 170 and the activelayer 120.

The tunnel barrier 160 may be disposed between the first conductivelayer 170 and the second conductive layer 140. The tunnel barrier 160may be disposed under the second conductive type semiconductor layer130.

The first electrode 172 may be electrically connected to the firstconductive layer 170. The first electrode 172 may be disposed under thefirst conductive layer 170. The first electrode 144 may be electricallyconnected to the first conductive layer 140. The second electrode 144may be disposed under the second conductive layer 140. The secondelectrode 144 and the first conductive layer 170 may be insulated fromeach other by the insulation layer 150.

Each of the first electrode 172 and the second electrode 144 may beformed of at least one material of Ti, Al, In, Ta, Pd, Co, Ni, Si, Ge,Ag, Au, Hf, Pt, Ru, and Au or alloys thereof and have a single or multilayer structure. The first and second electrodes 172 and 144 may supplya power into the first and second conductive type semiconductor layers110 and 130, respectively.

The first electrode 172 may be disposed under the first conductive layer144. The first electrode 172 and the second electrode 144 may beconnected to an external power source in a flip-chip bonding type.

The insulation layer 150, the first electrode 172, and the secondelectrode 144 may be disposed at various positions according to theirdesign. Also, the layer 150, the first electrode 172, and the secondelectrode 144 may be variously varied in formation method and orderaccording to their design.

FIG. 13 is a sectional view of a light emitting device packagecomprising the light emitting device according to an embodiment.

Referring to FIG. 13, the light emitting device package according to anembodiment may comprise a body 20, a first electrode 31 and a secondelectrode 32, which are disposed on the body 20, the light emittingdevice 100 disposed on the body 20 and electrically connected to thefirst electrode 31 and the second electrode 32, and a molding member 40surrounding the light emitting device 100.

The body 20 may be formed of a silicon material, a synthetic resinmaterial, or a metal material. An inclined surface may be disposedaround the light emitting device 100.

The first electrode 31 and the second electrode 32 are electricallyseparated from each other and supply a power to the light emittingdevice 100. Also, the first electrode 31 and the second electrode 32 mayreflect light generated in the light emitting device 100 to improvelight efficiency, and may dissipate heat generated in the light emittingdevice 100 to the outside.

The light emitting device 100 may be disposed on the body 20 or on thefirst electrode 31 or the second electrode 32.

The light emitting device 100 may be electrically connected to the firstand second electrodes 31 and 32 through a wiring process, a flip-chipprocess, or a die bonding process.

The molding member 40 may surround the light emitting device 100 toprotect the light emitting device 100. The molding member 40 maycomprise a phosphor to vary a wavelength of light emitted form the lightemitting device 100.

The above-described light emitting device according to the embodimentmay be applied to a light unit. The light unit may comprise a structurein which a plurality of light emitting devices is arrayed. The lightunit may be applied to the display device of FIGS. 13 and 14 and alighting device of FIG. 15. Also, the light unit to which the lightemitting device according to the embodiment is applied may be applied toillumination lamps, traffic lights, vehicle headlights, signs, andtelevisions.

FIG. 14 is an exploded perspective view illustrating a display deviceaccording to an embodiment.

Referring to FIG. 14, a display unit 1000 may comprise a light guideplate 1041, a light emitting module 1031 providing light to the lightguide plate 1041, a reflective member 1022 under the light guide plate1041, an optical sheet 1051 on the light guide plate 1041, a displaypanel 1061 on the optical sheet 1051, and a bottom cover 1011 receivingthe light guide plate 1031, the light emitting module 1031, and thereflective member 1022, but is not limited thereto.

The bottom cover 1011, the reflective member 1022, the light guide plate1041, and the optical sheet 1051 may be defined as the light unit 1050of the display device.

The light guide plate 1041 diffuses light to produce planar light. Thelight guide plate 1041 may be formed of a transparent material. Forexample, the light guide plate 1041 may be formed of one of an acrylicresin-based material such as polymethylmethacrylate (PMMA), apolyethylene terephthalate (PET) resin, a poly carbonate (PC) resin, acyclic olefin copolymer (COC) resin, and a polyethylene naphthalate(PEN) resin.

The light emitting module 1031 is disposed to provide light to the atleast one lateral surface of the light guide plate 1041. Thus, the lightemitting module 1031 may be used as a light source of a display device.

At least one light emitting module 1031 may be disposed on one lateralsurface of the light guide plate 1041 to directly or indirectly providelight. The light emitting module 1031 may comprise a board 1033 and thelight emitting device 200 according to the embodiment. The lightemitting device 200 may be arrayed by a predetermined distance on theboard 1033.

The board 1033 may be a printed circuit board (PCB) comprising a circuitpattern. The board 1033 may comprise a metal core PCB (MCPCB) or aflexible PCB (FPCB) as well as a general PCB, but is not limitedthereto. When the light emitting device 200 are mounted on a lateralsurface of the bottom cover 1011 or on a heatsink plate, the board 1033may be removed. Here, a portion of the heatsink plate may contact a topsurface of the bottom cover 1011.

The plurality of light emitting device 200 may be mounted on the board1033 to allow a light emitting surface through which light is emitted tobe spaced a predetermined distance from the light guide plate 1041, butis not limited thereto. The light emitting device 200 may directly orindirectly provide light to a light incident surface that is a sidesurface of the light guide plate 1041, but is not limited thereto.

The reflective member 1022 may be disposed below the light guide plate1041. Since the reflective member 1022 reflects light incident onto anunder surface of the light guide plate 1041 to supply the light upward,brightness of the light unit 1050 may be improved. For example, thereflective member 1022 may be formed of one of PET, PC, and PVC, but isnot limited thereto. The reflective member 1022 may be the top surfaceof the bottom cover 1011, but is not limited thereto.

The bottom cover 1011 may receive the light guide plate 1041, the lightemitting module 1031, and the reflective member 1022. For this, thebottom cover 1011 may comprise a receiving part 1012 having a box shapewith an opened upper side, but is not limited thereto. The bottom cover1011 may be coupled to a top cover (not shown), but is not limitedthereto.

The bottom cover 1011 may be formed of a metal material or a resinmaterial. Also, the bottom cover 1011 may be manufactured using a pressmolding process or an extrusion molding process. The bottom cover 1011may be formed of a metal or non-metal material having superior heatconductivity, but is not limited thereto.

For example, the display panel 1061 may be a liquid crystal display(LCD) panel, and comprise first and second boards formed of atransparent material and a liquid crystal layer between the first andsecond boards. A polarizing plate may be attached to at least onesurface of the display panel 1061. The present disclosure is not limitedto the attached structure of the polarizing plate. The display panel1061 may display information using light emitted from the light emittingmodule 1051. The display unit 1000 may be applied to various portableterminals, a monitor for a notebook computer, a monitor for a laptopcomputer, television, etc.

The optical sheet 1051 is disposed between the display panel 1061 andthe light guide plate 1041 and comprises at least one transmissionsheet. For example, the optical sheet 1051 may comprise at least one ofa diffusion sheet, a horizontal or vertical prism sheet, a brightnessenhanced sheet, etc. The diffusion sheet diffuses incident light, andthe horizontal or/and vertical prism sheet collects the incident lightinto a display region. In addition, the brightness enhanced sheet reuseslost light to improve the brightness. Also, a protection sheet may bedisposed on the display panel 1061, but is not limited thereto.

Here, optical members such as the light guide plate 1041 and the opticalsheet 1051 may be disposed on an optical path of the light emittingmodule 1031, but is not limited thereto.

FIG. 15 is a view of a display device according to an embodiment.

Referring to FIG. 15, a display apparatus 1100 may comprise a bottomcover 1152, a board 1020 on which the light emitting devices 200described above are arrayed, an optical member 1154, and a display panel1155.

The board 1020 and the light emitting device 200 may be defined as alight emitting module 1060. The bottom cover 1152, at least one lightemitting module 1060, the optical member 1154 may be defined as thelight unit.

The bottom cover 1152 may comprise a receiving part 1153, but is notlimited thereto.

Here, the optical member 1154 may comprise at least one of a lens, alight guide plate, a diffusion sheet, horizontal and vertical prismsheets, and a bright enhancement sheet. The light guide plate may beformed of a PC material or PMMA material. In this case, the light guideplate may be removed. The diffusion sheet diffuses incident light, andthe horizontal and vertical prism sheets collect the incident light intothe display panel 1155. The brightness enhanced sheet reuses lost lightto improve brightness.

The optical member 1154 is disposed on the light emitting module 1060 toproduce planar light using the light emitted from the light emittingmodule 1060 or diffuse and collect the light emitted from the lightemitting module 1060.

FIG. 16 is a perspective view of a lighting device according to anembodiment.

Referring to FIG. 16, the lighting unit 1500 may comprise a case 1510, alight emitting module 1530 disposed in the case 1510, and a connectionterminal 1520 disposed in the case 1510 to receive an electric powerfrom an external power source.

The case body 1510 may be formed of a material having good thermaldissipation properties, e.g., a metal material or a resin material.

The light emitting module 1530 may comprise a board 1532 and a lightemitting device 200 mounted on the board 1532. The light emitting device200 may be provided in plurality, and the plurality of light emittingdevice 200 may be arrayed in a matrix shape or spaced a predetermineddistance from each other.

The board 1532 may be an insulator on which a circuit pattern isprinted. For example, the board 1532 may comprise a general printedcircuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB,FR-4, etc.

Also, the board 1532 may be formed of a material which may effectivelyreflect light or be coated with a color by which light is effectivelyreflected, e.g., a white color or a silver color.

At least one light emitting device 200 may be disposed on the board1532. The light emitting device 200 may comprise at least one lightemitting diode (LED) chip. The LED may include color LEDs, whichrespectively emit light having a red color, a green color, a blue color,and a white color and an ultraviolet (UV) LED emitting UV rays.

The light emitting module 1530 may have a combination of several lightemitting devices 200 to obtain desired color and luminance. For example,the white LED, the red LED, and the green LED may be combined with eachother to secure a high color rendering index to obtain a high colorrendering index (CRI).

The connection terminal 1520 may be electrically connected to the lightemitting module 1530 to supply a power. The connection terminal 1520 maybe screwed and coupled to an external power source in a socket type, butis not limited thereto. For example, the connection terminal 1520 mayhave a pin shape, and thus, be inserted into the external power source.Alternatively, the connection terminal 1220 may be connected to theexternal power source by a wire.

In the above-described lighting device, at least one of the light guidemember, the spread sheet, the light collecting sheet, the brightnessenhancement sheet, and the fluorescent sheet is disposed in the path oflight emitted from the light emitting module to obtain an intendedoptical effect.

Embodiments provide a light emitting device having a new structure, amethod of fabricating the light emitting device, and a light unit.

Embodiments also provide a light emitting device in which a lightemitting structure layer is protected from the electrostatic discharge(ESD), a method of fabricating the light emitting device, and a lightunit.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A light emitting device comprising: a light emitting structure layercomprising a first conductive type semiconductor layer, an active layerunder the first conductive type semiconductor layer, and a secondconductive type semiconductor layer under the active layer; a firstconductive layer under the second conductive type semiconductor layerand electrically connected to the first conductive type semiconductorlayer; a second conductive layer under the second conductive typesemiconductor layer and electrically connected to the second conductivetype semiconductor layer; an insulation layer between the firstconductive layer and the second conductive layer; and a tunnel barrierunder the second conductive type semiconductor layer and disposedbetween the first conductive layer and the second conductive layer. 2.The light emitting device according to claim 1, wherein the tunnelbarrier has a thickness less than that of the insulation layer.
 3. Thelight emitting device according to claim 1, wherein the tunnel barrieris formed of the same material as that of the insulation layer or amaterial different from that of the insulation layer.
 4. The lightemitting device according to claim 1, wherein the tunnel barrier isformed of at least one of nitride, oxide, and fluoride.
 5. The lightemitting device according to claim 1, wherein the tunnel barrier has athickness of about 1 nm to about 20 nm.
 6. The light emitting deviceaccording to claim 1, wherein the tunnel barrier is formed of at leastone of Al₂0₃, Si0₂, SiN_(x), Ti0₂, MgF₂.
 7. The light emitting deviceaccording to claim 1, wherein the first conductive layer is disposed ina recess passing through a portion of the second conductive typesemiconductor layer and a portion of the active layer to contact thefirst conductive type semiconductor layer.
 8. The light emitting deviceaccording to claim 7, wherein the insulation layer is disposed withinthe recess to insulate the first conductive layer from the secondconductive type semiconductor layer.
 9. The light emitting deviceaccording to claim 1, further comprising an electrode electricallyconnected to the second conductive layer.
 10. The light emitting deviceaccording to claim 9, wherein the electrode is formed of at least one ofTi, Al, In, Ta, Pd, Co, Ni, Si, Ge, Ag, Au, Hf, Pt, Ru, and Au.
 11. Thelight emitting device according to claim 9, wherein the electrode isdisposed on the second conductive layer.
 12. The light emitting deviceaccording to claim 9, wherein the electrode is disposed under the secondconductive layer.
 13. The light emitting device according to claim 1,further comprising a conductive support substrate under the firstconductive layer.
 14. The light emitting device according to claim 1,wherein the second conductive layer is disposed between the secondconductive type semiconductor layer and the tunnel barrier.
 15. A lightunit comprising: a board; a light emitting device on the board; and anoptical member through which light provide from the light emittingdevice is transmitted, wherein the light emitting device comprises: alight emitting structure layer comprising a first conductive typesemiconductor layer, an active layer under the first conductive typesemiconductor layer, and a second conductive type semiconductor layerunder the active layer; a first conductive layer under the secondconductive type semiconductor layer and electrically connected to thefirst conductive type semiconductor layer; a second conductive layerunder the second conductive type semiconductor layer and electricallyconnected to the second conductive type semiconductor layer; aninsulation layer between the first conductive layer and the secondconductive layer; and a tunnel barrier under the second conductive typesemiconductor layer and disposed between the first conductive layer andthe second conductive layer.
 16. The light unit according to claim 15,wherein the tunnel barrier has a thickness less than that of theinsulation layer.
 17. The light unit according to claim 15, wherein thetunnel barrier is formed of the same material as that of the insulationlayer or a material different from that of the insulation layer.
 18. Thelight unit according to claim 15, wherein the tunnel barrier is formedof at least one of nitride, oxide, and fluoride.
 19. The light unitaccording to claim 15, wherein the tunnel barrier is formed of at leastone of Al₂0₃, Si0₂, SiN_(x), Ti0₂, MgF₂.
 20. The light unit according toclaim 15, wherein the first conductive layer is disposed in a recesspassing through a portion of the second conductive type semiconductorlayer and a portion of the active layer to contact the first conductivetype semiconductor layer.